Titanium alkoxides for the fast ruthenium-catalyzed living radical polymerization of methyl methacrylate

Abstract

A series of metal alkoxides [M(Oi-Pr)n (M=Al, Sn, Ti, Zr, Sc) and Ti(OR)4 (R = Me, Et, i-Pr, t-Bu, Ph)] were examined as additives for rate enhancement and finer reaction control in the living radical polymerization of methyl methacrylate (MMA) with RuCl2 (PPh3)3. All the additives induced a faster polymerization than in their absence and gave polymers with controlled molecular weights and narrow molecular weight distributions (MWDs) (Mw/Mn = 1.1-1.3). Ti(Oi-Pr 4 was the most effective in terms of the rate and the controllability and was effective in the synthesis of a high molecular weight polymer with a narrow MWD (Mn = 100900, Mw/Mn = 1.11). 1H NMR analysis showed that the added titanium alkoxide interacted with RuCl2(PPh3)3 to generate a more active catalyst.